Use of polyolefin waxes in hot melt compositions

Abstract

Hot melt compositions are based on isotactic, low molecular mass, low viscosity homopolymer or copolymer waxes, atactic polyalpha-olefins (APAOs), and a resin fraction below 20% by weight. Hot melt compositions of this kind can be used with outstanding effect as hot melt adhesives.

1 . A hot melt composition comprising 
 a) one or more isotactic homopolymer, isotactic copolymer waxes or a mixture thereof, wherein the one or more waxes include the monomers ethylene, propylene, higher linear or branched aipha-olefins having 4 to 20 carbon atoms or a combination thereof, the one or more waxes, based on the total weight of the one or more waxes, containing 0.1% to 30% by weight of structural units originating from one monomer and 70% to 99.9% by weight of structural units from the other monomer or monomers, wherein the one or more waxes have a weight-average molecular weight M w  of less than or equal to 40 000 g/mol, wherein the one or more waxes are obtained by metallocene catalysis, wherein the one or more waxes have a dropping point or ring & ball softening point of between 80 and 165° C., a melt viscosity, measured at a temperature of 170° C., of between 20 and 40 000 mPa·s, and a glass transition temperature, T g , of not more than −20° C.,    b) one or more amorphous, atactic polyalpha-olefins,    c) one or more resins, the weight fraction of the one or more resins, based on the hot melt composition, being below 20% by weight.    
   
   
       2 . The hot melt composition as claimed in  claim 1 , comprising 
 a) one or more isotactic homopolymer waxes, isotactic copolymer waxes comprising the monomers ethylene, propylene or both, the one or more waxes, based on the total weight of the one or more waxes, containing 0.1% to 30% by weight of structural units originating from one monomer and 70% to 99.9% by weight of structural units from the other monomer.    
   
   
       3 . The hot melt composition as claimed in  claim 1 , comprising 
 a) one or more isotactic propylene homopolymer waxes isotactic propylene copolymer waxes, or a mixture thereof, the one or more waxes waxes, based on the total weight of the one or more waxes, containing 0.1% to 30% by weight of structural units originating from ethylene and 70% to 99.9% by weight of structural units from propylene.    
   
   
       4 . The hot melt composition as claimed in  claim 1 , comprising 
 a) one or more homopolymer waxes or copolymer waxes originating from ethylene and at least one branched or unbranched 1-alkene having 3 to 20 carbon atoms, the amount of structural units from the branched or unbranched 1-alkene having 3 to 20 carbon atoms in the one or more waxes being in the range from 0.1% to 30% by weight.    
   
   
       5 . The hot melt composition as claimed in  claim 1 , wherein the one or more waxes have a number-average molar mass M n  of between 500 and 20 000 g/mol, and a weight-average molar mass M w  of between 1000 and 40 000 g/mol.  
   
   
       6 . The hot melt composition as claimed in  claim 1 , comprising 
 a) 0.1% to 39% by weight of the one or more waxes, and 
 a) 61% to 95% by weight of the one or more amorphous atactic polyalpha-olefins.  
   
   
   
       7 . A hot melt adhesive comprising the hot melt composition as claimed in  claim 1 .  
   
   
       8 . The hot melt composition as claimed in  claim 1 , wherein the weight fraction of the one or more resins, based on the hot melt composition, is between 1% and 18% by weight.  
   
   
       9 . The hot melt composition as claimed in  claim 1 , wherein the weight fraction of the one or more resins, based on the hot melt composition, is between 5% and 15% by weight.  
   
   
       10 . The hot melt composition as claimed in  claim 1 , wherein the weight fraction of the one or more resins, based on the hot melt composition, is between 8% and 12% by weight.  
   
   
       11 . The hot melt composition as claimed in  claim 1 , wherein the weight fraction of the one or more resins, based on the hot melt composition, is between 10% and 12% by weight.  
   
   
       12 . The hot melt composition as claimed in  claim 1 , wherein the one or more waxes have a number-average molar mass M n  of between 800 and 10 000 g/moland a weight-average molar mass M w  of between 1600 and 30 000 g/mol.  
   
   
       13 . The hot melt composition as claimed in  claim 1 , wherein the one or more waxes have a number-average molar mass M n  of between 1000 and 5000 g/mol, and a weight-average molar mass M w  of between 2000 and 25 000 g/mol.